x402-gated card transaction endpoint on Base, paying $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a card transactions resource at `/api/v1/cards/44/transactions` via the x402 payment protocol. It is part of a broader platform that offers dozens of pay-per-call API endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities — all priced at $0.02 per request settled in USDC on the Base network.
The specific endpoint listed here accepts POST requests and is gated by an x402 challenge requiring a maximum of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) per call. Payment is made to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using the USDC contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` on Base. No API keys or rate limits are advertised; access is instant once payment is included in the `X-PAYMENT` header.
Documentation on the site is extremely sparse — the docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI schema, no request/response examples, and no description of what the `/cards/44/transactions` resource actually returns or what input it expects. The endpoint name suggests card transaction data (possibly payment-card or gift-card related), but this is speculative. The platform's landing page confirms the pricing model and lists many other endpoints, but provides no technical detail for any of them.
Capabilities
Use cases
- —Retrieving card transaction data on a per-call payment basis without API keys
- —Integrating card transaction lookups into agent workflows that settle via x402/USDC on Base
- —Programmatic access to transaction records for card ID 44
Fit
Best for
- —Developers wanting keyless, pay-per-use API access settled in USDC on Base
- —AI agents that can autonomously pay for API calls via x402
- —Users who need occasional card transaction data without subscription commitments
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume consumers who would benefit from bulk pricing or subscription plans
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/44/transactions \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, confirming pricing and payment details. However, there is no documentation, no OpenAPI schema, no request/response examples, and no explanation of what the endpoint actually does. The docs pages are empty. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet' with no content.
- —No OpenAPI or request/response schema provided; the purpose of /api/v1/cards/44/transactions is unclear.
- —The hardcoded card ID '44' in the URL path is unexplained — it is unknown whether other card IDs are supported or what they represent.
- —Cannot verify what data this endpoint returns or what POST body it expects.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/44/transactions
- —All endpoints on the platform are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC contract address on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/44/transactions